Scientific Programme
Sports and Exercise Medicine and Health
IS-MH05 - Is there power after disuse? Insights into the effects of sedentarism, bed rest, hospitalization and recovery on muscle mass, muscle function, fatigability, and physical performance in older people
Date: 04.07.2024, Time: 10:00 - 11:15, Lecture room: Lomond Auditorium
Description
Aging is accompanied by losses in muscle mass, strength and power that result in a decline in physical performance and functional capacity among aged individuals. Although it is most often suggested that these age-related declines occur progressively and steadily, it may occur discontinuously. Thus, age trajectories of muscle function may describe abrupt declines along with partial recoveries and maintenance phases that, over the long term, lead to the declines observed in older individuals. These cycles may be the result of repeated acute conditions or events that negatively impact muscle mass, function, and functional capacity, such as a fall, hospitalization, or chronic disease exacerbation. These negative events usually have in common the induction of the patient to relatively long periods of disuse (e.g. bed rest) which aggravate the effects of aging if countermeasures are not applied to return individuals to their pre-decline levels. Therefore, the aim of this session will be to provide novel evidence on the effects of various degrees of disuse (from sedentary behavior during daily living to bed rest and hospitalization) and recovery strategies on muscle mass, muscle function, and physical performance in older individuals. This presentation is intended for researchers and practitioners interested in better understanding the physiological determinants of disuse-induced neuromuscular impairments and the efficacy of recovery strategies.
Chair(s)
Julian Alcazar
University of Castilla-La Mancha, Faculty of Sports Science
Spain
Chris Easton
University of the West of Scotland, Institute for Clinical Exercise and Health Science
United Kingdom
Speaker A
Marta Colosio
University of Pavia, Molecular Medicine
Italy
Read CVECSS Glasgow 2024: IS-MH05
Worsening of neuromuscular function after disuse and beneficial effects of aerobic reconditioning in older people
Muscle strength and power are essential components for maintaining functional ability in old age, especially in weight-bearing movements such as climbing stairs and rising from a chair. Adequate levels of muscle power are also essential to prevent and counteract deterioration of postural control and thus prevent falls. Disuse can drastically reduce muscle power in the lower extremities, compromising mobility and overall quality of life. Bed rest, which is a recognized experimental model for inducing substantial muscle dysfunction in a matter of weeks, markedly compromises muscle power generation. This negative impact on neuromuscular function can be exacerbated when disuse is applied to aging muscle. In addition, it is often assumed that disuse may also decrease resistance to muscle fatigue due, at least in part, to disuse-induced changes in muscle energy and blood flow. However, human studies investigating disuse-induced changes in muscle fatigue endurance yield equivocal results, with approximately equal numbers of studies reporting a reduction in fatigue resistance, no change in fatigue resistance, and an increase in fatigue resistance. Finally, resistance and/or endurance training sessions performed after disuse promote recovery of muscle mass and power but may not restore muscle power to pre-disuse values in older individuals. This session will summarize recent data on the impact of disuse on performance fatigability in older adults and how training can mitigate or aid in the recovery of muscle strength and power. In addition, the presentation will explore new findings on the force-velocity-power relationship and performance fatigability obtained from the latest bed rest campaign, in which older adults were forced to stay in bed for 10 days and then trained with endurance exercise for 21 days.
Speaker B
Julian Alcazar
University of Castilla-La Mancha, Faculty of Sports Science
Spain
Read CVECSS Glasgow 2024: IS-MH05
The impact of sedentary behavior and bed rest on physical performance and sit-to-stand muscle power in middle-aged and older people
Muscle power is one of the best predictors of physical performance in a wide variety of populations, from young adults to older people. Changes in muscle power with age are well described in the literature, but the factors leading to these changes are poorly understood. Apart from the effect of age per se, lifestyle factors, such as sedentary behavior, may play an important role in the age trajectories of muscle power and physical performance, even independently of physical activity patterns. In this regard, not only the total amount of time spent in sedentary activities, but how this time is distributed throughout the day (e.g. morning vs. evening), or how often it is interrupted, may have a profound effect on muscle power and physical performance among middle-aged and older individuals. Furthermore, understanding the interaction of these patterns with physical activity and exercise training may improve the prescription and recommendation of different doses of physical activity and exercise training for each profile of sedentary behavior. These personalized strategies may prevent or minimize the loss of muscle power and functional capacity observed with aging and could be easily implemented using wearables. Thus, the present lecture will provide new insights into the relationship between different patterns of sedentary behavior, sit-to-stand muscle power and functional capacity in middle-aged people and older people, and the interaction with physical activity and exercise training. In addition, this presentation will share novel findings on the effects of severe sedentary behavior (bed rest) on sit-to-stand muscle power and physical performance in older people, and how these effects are regulated by the inclusion of an exercise-based pre-habilitation program and the implementation of an exercise-based recovery program.
Speaker C
Charlotte Suetta
Rigshospitalet, University of Copenhagen, Department of Clinical Physiology, Nuclear Medicine and PET
Denmark
Read CVECSS Glasgow 2024: IS-MH05
NMES as a countermeasure to loss of muscle mass during bed rest and hospitalization
Loss of muscle mass represents a common phenotypic trait associated with bed rest, hospitalization, and critical illness. The repeated cycles of disuse-induced atrophy, followed by incomplete muscle recovery, have been proposed as a significant contributor to the development of sarcopenia, which in turn increases the risk of morbidity, dependency, and mortality. Nevertheless, there is a limited body of research that has endeavored to elucidate the molecular regulators of muscle mass loss in older individuals following bed rest. Consequently, the mechanistic drivers remain unresolved, and aside from resistance exercise, there are currently no effective therapeutic strategies to mitigate muscle wasting and loss of function in hospitalized patients. While Neuromuscular Electrical Stimulation (NMES) may not be as effective as resistance exercise, it could serve as an alternative for patient populations that are critically ill and/or challenging to mobilize. This presentation will explore the influence of age and sex on the effects of enforced bed rest and evaluate NMES as a potential countermeasure.